I believe, essentially, Berserk is a story about the strength to overcome suffering and despair. I remember a line somewhere about Apostles being humans who couldn't face up to their weakness, perpetually running away from themselves, and eventually succumbed.

I wonder if the case is then that humans, suffering at the hands of the weak, insane, and impotent, desperately craved some higher purpose to their suffering, and that the more mundane explanation of human folly was just not "exciting" or "satisfying" enough. Not to mention the fact that most people don't want to own up to their issues. And this is what created the Idea of Evil and, by extension, Beherits, as a kind of metaphysical get out of jail free card from their self-imposed despair.

So I think the IoE's causality has become a self-perpetuating system that answers earthly despair with "divine" grace. I think Guts is outside the current precisely because he's got the balls and willpower to face darkness, both within and without.

I think the thematic end of the series will be humanity finding an inner strength that is greater than the pain and horror that compels someone to trade the life of a loved one for a demonic pseudo-life.

This definitely how I read the situation. When faced with hardship, humans have a tendency to turn to God and reassure themselves that their suffering must serve some higher purpose. And this gestalt desire gave birth to a god which exists to provide that justification.

So I think the IoE's causality has become a self-perpetuating system that answers earthly despair with "divine" grace. I think Guts is outside the current precisely because he's got the balls and willpower to face darkness, both within and without.

Beherits float up from the deepest layers of the abyss as we see during voume 13. Sent out as tiny summons to the Idea of Evil's realm. I think that the ambiguity of "justify suffering" may have led to an infinite feedback loop, in which human suffering serves the higher purpose of fuelling a god, who elects God Hands, seeds the the world with beherits, and creates apostles without any clear goal of what it's all leading towards except maintaining the suffering that sustains it. unless that is Griffith's current purpose after all, and we have finally reached the proposed final product of all the injustice in the world. Not too sure about that.

And Guts falls outside of it because he's not the sort to start questioning God when things go to shit. He's been in this situation since he was born. He just grits his teeth and does what he needs to do try and get out of it. And this message of self sufficiency has been passed on to the people he meets. First (probably unsuccessfully) with Theresia, then it became Jill's final lesson, which she took to heart, and of course his current party, most notably Farnese and Serpico.

I think the thematic end of the series will be humanity finding an inner strength that is greater than the pain and horror that compels someone to trade the life of a loved one for a demonic pseudo-life.

The tragedy is that if everyone had the same outlook as Guts, the Idea would not exist. If the entire world went a step further and became wholly optimistic, then maybe a God would be born to combat suffering, or grant humans the individual strength to face it. And that's the only way something like the Idea could ever be defeated, not simply diving down and stabbing it à la Sea God, or even anything Femto could pull together (because a lot of people talk about him "betraying and dethroning" the Idea. I think that's the ultimate destiny of magic in this story, to serve as a new ideological perspective for humans that stops them inadvertently turning to the Idea.

Miura has done his research with the magic aspect of the series. His metaphysics is pretty much a grimdark version of the Platonic system, and these philosophies are precisely about finding an inner strength to overcome the world and all that.

Humans will need to adapt, period. They'll have to set aside their differences, start tolerating those that are different and respect nature, in the same way wizards and witches do. No amount of magic puf puf will make evil dissapear completely, that much is clear. But, there might be methods to prevent the rise of it from happening ever again once IOE and its agents are dealth with.